Last night I ran a group of playtesters through the first game of what I'm tentatively calling Into the Odd. I used the dungeon I hope to include with the final game and use again beforehand, so I'll avoid too any spoilers. Needless to say the result was a total party kill after a good amount of time exploring. Reactions were mixed, but I think it was mostly successful.
I might write a more thorough play report another time, but for now I'd like to talk about the changes I've made in the wake of the playtest.
Arcana - No longer fire-or-die.
Previously, tanking your INT Save when you casted a spell from your Arcanum meant the spell would backfire on you or cause damage, which could be quite lethal. While I liked the idea of this deadliness it seemed a little too binary. Either the spell would be too risky and wasn't worth attempting or it was safe enough to try, holding the lingering risk of an anticlimactic death.
I've moved back to something with more in common with D&D's traditional Vancian casting. When you fail your INT Save the spell isn't cast and cannot be used again until the Arcanum has "rested" for a number of hours equal to its highest currenty disabled spell. This means if you blow it on a Power 14 (D&DLevel 7) Spell you're going to have to shoulder your Arcanum for some time if you want to get it back. Nothing stopping you from continuing to use the other spells, but even if you fizzle on a lower powered spell you've got that big wait from the high powered spell before any of them are restored.
Starting Arcanum - Now a Win/Win Situation
Previously you rolled 3d6 to see if you got an Arcanum at chargen. If it was equal or under your INT score then you got one with that Power Total, otherwise you got nothing. Really this was just punishing players that had already had a bad roll on their INT score, giving lucky rollers yet another bonus. In addition, as much as I enjoy fully random chargen, players seem to at least want to choose between being a caster or non-caster. Now this is a choice you can make at chargen regardless of your Ability Scores.
After rolling their Abilities the player rolls another 3d6. They either take an Arcanum with this Power Total or they replace one of their Ability Scores with this number. Keeps the random element with a simple choice that isn't too daunting for new players. If in doubt just stick it in your lowest Ability Score.
Expertise - Gone!
Gone entirely. While I liked the idea I didn't think it was implemented well and was a little daunting in chargen. I might add in a new system for this but for now it's out. I'm happy to look at a character's fluff to consider what clues they might be able to get particular insight from.
Transfering Spells - Upgrading your Arcanum
Upgrading is an ugly word, but I like the idea of being able to move spells from an Arcanum you've found onto your own. It particularly suits a character using a Spellbook for their Arcanum. For now I'm using the mechanic below.
Transferring Spells: Most Arcana can have spells moved to and from it. Do to this the character must be bonded to the Arcanum a spell is being transferred to. They cast a spell with another Arcanum, targetting their bonded Arcanum, and if cast successfully the Spell will move over to the bonded Arcanum, leaving the other one. However, if the character cannot pass an INT Save vs the bonded Arcanum’s new Power Total (including the spell being transfered) then the spell is lost in transfer and they take 1d6 damage.
May change this in future but I particularly like that as an Arcanum becomes "full" it's more risky to try to add new spells to it. I envisage most high powered spells being bound to large, immobile Arcana like altars and statues, with noone daring to try and move them elsewhere.